CA1334091C - Radioactive catalyst and oxidation-reduction method and apparatus using same - Google Patents
Radioactive catalyst and oxidation-reduction method and apparatus using sameInfo
- Publication number
- CA1334091C CA1334091C CA000612542A CA612542A CA1334091C CA 1334091 C CA1334091 C CA 1334091C CA 000612542 A CA000612542 A CA 000612542A CA 612542 A CA612542 A CA 612542A CA 1334091 C CA1334091 C CA 1334091C
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- Prior art keywords
- radioactive
- catalyst
- oxidation
- semiconductor
- reduction reaction
- Prior art date
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- 239000003054 catalyst Substances 0.000 title claims abstract description 52
- 230000002285 radioactive effect Effects 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims description 13
- 230000033116 oxidation-reduction process Effects 0.000 title claims description 10
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 24
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000001257 hydrogen Substances 0.000 claims abstract description 21
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 21
- 230000005855 radiation Effects 0.000 claims abstract description 20
- 238000006479 redox reaction Methods 0.000 claims abstract description 20
- 239000004065 semiconductor Substances 0.000 claims abstract description 19
- 239000002245 particle Substances 0.000 claims abstract description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000001301 oxygen Substances 0.000 claims abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 11
- 239000010419 fine particle Substances 0.000 claims abstract description 10
- 239000012530 fluid Substances 0.000 claims description 11
- KJTLSVCANCCWHF-BKFZFHPZSA-N ruthenium-106 Chemical compound [106Ru] KJTLSVCANCCWHF-BKFZFHPZSA-N 0.000 claims description 7
- 239000002915 spent fuel radioactive waste Substances 0.000 claims description 7
- 239000000956 alloy Substances 0.000 claims description 3
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 description 18
- 239000011941 photocatalyst Substances 0.000 description 10
- 238000000354 decomposition reaction Methods 0.000 description 8
- 238000012423 maintenance Methods 0.000 description 4
- 239000002901 radioactive waste Substances 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- 238000010420 art technique Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000010808 liquid waste Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- BHMLFPOTZYRDKA-IRXDYDNUSA-N (2s)-2-[(s)-(2-iodophenoxy)-phenylmethyl]morpholine Chemical compound IC1=CC=CC=C1O[C@@H](C=1C=CC=CC=1)[C@H]1OCCNC1 BHMLFPOTZYRDKA-IRXDYDNUSA-N 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- -1 hydroxyl ions Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000000941 radioactive substance Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
- C01B3/04—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by decomposition of inorganic compounds, e.g. ammonia
- C01B3/042—Decomposition of water
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
- Y02P20/133—Renewable energy sources, e.g. sunlight
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Combustion & Propulsion (AREA)
- Inorganic Chemistry (AREA)
- Catalysts (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Oxygen, Ozone, And Oxides In General (AREA)
Abstract
A radioactive catalyst is disclosed which comprises a fine particle of semiconductor and a high radioactive platinum group element deposited on the particle of semiconductor. The radioactive catalyst serves as a source of radiation and also as a catalyst for oxidation-reduction reaction. By bringing the radioactive catalyst into contact with water, the water is decomposed by the oxidation-reduction reaction to produce hydrogen and oxygen.
Description
- 1 3340~ 1 RADIOACTIVE CATALYST AND OXIDATION-REDUCTION
METHOD AND APPARATUS USING SAME
FIELD OF THE INVENTION
The present invention relates to a radioactive catalyst which ~E se serves as a source of reaction energy for an oxidation-reduction (redox) reaction and has also a catalytic action, and also relates to an oxidation-reduction technique using the radioactive catalyst.
There has already been known in the art a technique of using a catalyst prepared by depositing a platinum group element on a fine particle of semiconductor and irradiating light from outside to the catalyst to cause an oxidation-reduction reaction. The catalyst of this kind is referred to as a "photocatalyst". The oxidation-reduction reaction using the photocatalyst has drawn an increasing attention as one of the methods of solar energy development and vigorous research and development has been carried out. An attempt has been made to produce hydrogen and oxygen by decomposing water with such a technique, for example, and to use these products as an electrical or thermal energy.
However, decomposition efficiency of water by light in accordance with the prior art technique is so low that the prospect of practical utilization is still far from certain.
This is because, in order to form electron-hole pairs in the - 1 3340q 1 semiconductor of the photocatalyst and to cause the oxidation-reduction reaction, photons of a photo-energy of at least about 3 eY are necessary and only a limited ultra-violet range of light can be utilized.
In addition, the following practical problems are left yet unsolved. Namely, an apparatus must be made of a transparent material in order to utilize solar energy and since irradiation of light is made only unidirectionally, the rays of light cannnot irradiate all of the fine particles of the photocatalyst if the concentration of the photocatalyst particles is high. Therefore, the apparatus using the photocatalyst becomes large plane-wise.
Furthermore, the operation of the apparatus depends on weather and day and night. Thus, there are various problems yet to be solved in fabrication and installation of the apparatus.
On the other hand, the production of hydrogen and oxygen by decomposition of water has been carried out by electrolysis at present and involves the problem of an extremely lare quantity of electric energy required therefor SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a novel catalyst and an oxidation-reduction technique using such a novel catalyst which can solve the above-described prior art problems and which can efficiently conduct the oxidation-reduction reaction and can proceed with the reaction successively without the use of solar energy having some limitations and without substantial maintenance of equipment.
It is another object of the present invention to provide a technique which can effectively utilize high radioactive wastes and can thereby obtain clean energy.
hccording to the present invention, the above-described objects can be accomplished by a radioactive catalyst which comprises a fine particle of semiconductor and a high radioactive platinum group element deposited on the particle of semiconductor. Thus the radioactive catalyst can serve as a source of radiation of reaction energy and also has a catalytic action for oxidation-reduction reaction.
The term "radioactive catalyst" used herein has been created by the inventors of the present invention on the basis of the conventional term "photocatalyst" and has not yet been established scientifically. Such a novel term has inevitably been employed for convenience sake, since a catalyst having both the radiation source and the catalytic action has not yet been known in the art and a suitable term is not therefore known.
According to another aspect of the present invention, there is provided an oxidation-reduction method which comprises bringing the above-described radioactive catalyst into contact wiht a fluid to be processed to produce electron-hole pairs in the semiconductor of said catalyst by the radiation generated from said high radioactive platinum group element deposited on said semiconductor particle, thereby causing the oxidation-reduction reaction. By using the oxidation-reduction method of the present invention, oxygen and hydrogen can be produced from water.
According to other aspect of the present invention, there is provided an oxidation-reduction apparatus which comprises a container in which the above-described radioactive catalyst is packed, means for supplying a fluid to be processed into said container, and means for discharging produts of oxidation-reduction reaction from said cont~iner.
The high radioactive platinum group elements such as, for example, ruthenium-106 and the likc can be recovered from a spent nuclear fuel. These metals have conventionally been discarded as high radioactive wastes, but can effectively be utilized as a new energy source according to the present invention.
The high radioactive platinum element deposited on the semiconductor particle is Per se an energy source and generates radiation. This radiation produces electron-hole pairs in the semiconductor particle. Energy of radiation is greater by about 105 to 106 times than energy of light.
Therefore, the oxidation-reduction reaction can be carried out at a high efficiency. If water is used as the fluid to be processed, for example, and is brought into contact with the radioactive catalyst, water can be decomposed efficiently.
The energy source used in the present invention is not the rays of light irradiated from outside as in the prior art technique but the radiation irradiated from inside, and thus the reaction proceeds throughout the radioactive catalyst even when any container or tube for containing the radioactive catalyst is employed. Also from this viewpoint, the efficiency of the reaction becomes extremely high.
As described above, since the radiation is generated from inside and irradiated in all directions, radiation spreads sufficiently even when the concentration of the particles of the radioactive catalyst becomes high and, since a higher concentration results in high effeciency, the apparatus can be made more compact in scale. Accordingly, various limitations resulted from the utilization of solar energy can be eliminated.
When various useful metals recovered from the spent nuclear fuel are used as the high radioactive platinum group element, effective utilization of the high radioactive wastes can be made and clean energy such as hydrogen and oxygen can be thereby produced.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an explanatory view showing a radioactive catalyst and its energy diagram in accordance with the present invention; and Fig. 2 is an explanatory view showing an example of a water decomposition apparatus using the radioactive catalyst of the present invention. 1 334091 PREFERRED EMBODIMENTS OF THE INVENTION
Fig. 1 is an explanatory view showing the radioactive catalyst and the oxidation-reduction reaction using the catalyst in accordance with the present invention. The respective particles of the radioactive catalyst 10 has a structure wherein a high radioactive platinum group element 14 such as ruthenium-106 is deposited or supported on a fine particle of n-type semiconductor 12 such as titanium oxide.
The platinum group elements recovered from the spent nuclear fuel can be employed as the platinum group element of the radioactive catalyst 10. Besides ruthenium, rhodium or palladium may be used as the platinum group element. From the aspect of high radioactivity, however, preferred is ruthenium-106.
The fluid to be processed is brought into contact with the radioactive catalyst 10. The example of the fluid to be processed is water. If water is used, hydrogen and oxygen can be produced by the oxidation-reduction reaction. In Fig. 1, the lower half represents an energy diagram. When the fine particle of semiconductor 12 is excited by the high radiation energy generated from the radioactive platinum gruop element 14, electrons are produced and gathered at the conduction band (C.B.) while positive holes are produced and gathered at the valence band (~.B.). The radiation energy generated from the high radioactive platinum group element 14 is from about 105 to about 106 eV and is by far greater than the band gap of the fine particle of semiconductor 12 so that a large number of electron-hole pairs can be formed.
The oxidation-reduction reaction such as the decomposition of water can be carried out by utilizing these large number of electron-hole pairs. In other words, hydrogen ions are reduced to hydrogen gas by the electrons in the conduction band while hydroxyl ions are oxidized to produce oxygen gas by the positive holes in the valence band. In the present invention, since the radioactive catalyst itself has the action of the generation source of the reaction energy as well as the action of the catalyst, the oxidation-reduction reaction can always be continued by merely bringing the fluid to be processed into contact with the catalyst.
The result of tentative calculation when hydrogen and oxygen are produced by using the radioactive catalyst of the present invention will be described hereinbelow. It is assumed that ruthenium-106 recovered from the spent nuclear fuel is used as the high radioactive platinum group element.
Radioactivity of ruthenium-106 is 3,300 Ci/g 106Ru. The radiation energy of about 500 keV resulted from l06Rh which is a decay product of 106Ru and in radiation equilibrium with 106Ru, is assumed to be all the energy contributed to the reaction, and the radiation energy resulted from the other ~ rays is neglected. All of this radiation energy are assumed to contribute to the formation of the electron- hole pairs and all of the resulting electron-hole pairs are assumed to contribute to the decomposition of water.
(1) Since the decay constant is 3.7 x 1010, the resulting electron-hole pairs per hour are given as follows:
' 3,300 Ci/g 106Ru x 3.7 x 101 x 5 x 105 eV/3eV x 60 min x 60 sec = 7.33 x 1022 (2) The amount of the produced hydrogen gas per hour is given as follows:
7.33 x 1022/2 x 6.02 x 1023 =6.07 x 10-2 mol H2/hr =1.35 Q H2/hr.
METHOD AND APPARATUS USING SAME
FIELD OF THE INVENTION
The present invention relates to a radioactive catalyst which ~E se serves as a source of reaction energy for an oxidation-reduction (redox) reaction and has also a catalytic action, and also relates to an oxidation-reduction technique using the radioactive catalyst.
There has already been known in the art a technique of using a catalyst prepared by depositing a platinum group element on a fine particle of semiconductor and irradiating light from outside to the catalyst to cause an oxidation-reduction reaction. The catalyst of this kind is referred to as a "photocatalyst". The oxidation-reduction reaction using the photocatalyst has drawn an increasing attention as one of the methods of solar energy development and vigorous research and development has been carried out. An attempt has been made to produce hydrogen and oxygen by decomposing water with such a technique, for example, and to use these products as an electrical or thermal energy.
However, decomposition efficiency of water by light in accordance with the prior art technique is so low that the prospect of practical utilization is still far from certain.
This is because, in order to form electron-hole pairs in the - 1 3340q 1 semiconductor of the photocatalyst and to cause the oxidation-reduction reaction, photons of a photo-energy of at least about 3 eY are necessary and only a limited ultra-violet range of light can be utilized.
In addition, the following practical problems are left yet unsolved. Namely, an apparatus must be made of a transparent material in order to utilize solar energy and since irradiation of light is made only unidirectionally, the rays of light cannnot irradiate all of the fine particles of the photocatalyst if the concentration of the photocatalyst particles is high. Therefore, the apparatus using the photocatalyst becomes large plane-wise.
Furthermore, the operation of the apparatus depends on weather and day and night. Thus, there are various problems yet to be solved in fabrication and installation of the apparatus.
On the other hand, the production of hydrogen and oxygen by decomposition of water has been carried out by electrolysis at present and involves the problem of an extremely lare quantity of electric energy required therefor SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a novel catalyst and an oxidation-reduction technique using such a novel catalyst which can solve the above-described prior art problems and which can efficiently conduct the oxidation-reduction reaction and can proceed with the reaction successively without the use of solar energy having some limitations and without substantial maintenance of equipment.
It is another object of the present invention to provide a technique which can effectively utilize high radioactive wastes and can thereby obtain clean energy.
hccording to the present invention, the above-described objects can be accomplished by a radioactive catalyst which comprises a fine particle of semiconductor and a high radioactive platinum group element deposited on the particle of semiconductor. Thus the radioactive catalyst can serve as a source of radiation of reaction energy and also has a catalytic action for oxidation-reduction reaction.
The term "radioactive catalyst" used herein has been created by the inventors of the present invention on the basis of the conventional term "photocatalyst" and has not yet been established scientifically. Such a novel term has inevitably been employed for convenience sake, since a catalyst having both the radiation source and the catalytic action has not yet been known in the art and a suitable term is not therefore known.
According to another aspect of the present invention, there is provided an oxidation-reduction method which comprises bringing the above-described radioactive catalyst into contact wiht a fluid to be processed to produce electron-hole pairs in the semiconductor of said catalyst by the radiation generated from said high radioactive platinum group element deposited on said semiconductor particle, thereby causing the oxidation-reduction reaction. By using the oxidation-reduction method of the present invention, oxygen and hydrogen can be produced from water.
According to other aspect of the present invention, there is provided an oxidation-reduction apparatus which comprises a container in which the above-described radioactive catalyst is packed, means for supplying a fluid to be processed into said container, and means for discharging produts of oxidation-reduction reaction from said cont~iner.
The high radioactive platinum group elements such as, for example, ruthenium-106 and the likc can be recovered from a spent nuclear fuel. These metals have conventionally been discarded as high radioactive wastes, but can effectively be utilized as a new energy source according to the present invention.
The high radioactive platinum element deposited on the semiconductor particle is Per se an energy source and generates radiation. This radiation produces electron-hole pairs in the semiconductor particle. Energy of radiation is greater by about 105 to 106 times than energy of light.
Therefore, the oxidation-reduction reaction can be carried out at a high efficiency. If water is used as the fluid to be processed, for example, and is brought into contact with the radioactive catalyst, water can be decomposed efficiently.
The energy source used in the present invention is not the rays of light irradiated from outside as in the prior art technique but the radiation irradiated from inside, and thus the reaction proceeds throughout the radioactive catalyst even when any container or tube for containing the radioactive catalyst is employed. Also from this viewpoint, the efficiency of the reaction becomes extremely high.
As described above, since the radiation is generated from inside and irradiated in all directions, radiation spreads sufficiently even when the concentration of the particles of the radioactive catalyst becomes high and, since a higher concentration results in high effeciency, the apparatus can be made more compact in scale. Accordingly, various limitations resulted from the utilization of solar energy can be eliminated.
When various useful metals recovered from the spent nuclear fuel are used as the high radioactive platinum group element, effective utilization of the high radioactive wastes can be made and clean energy such as hydrogen and oxygen can be thereby produced.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an explanatory view showing a radioactive catalyst and its energy diagram in accordance with the present invention; and Fig. 2 is an explanatory view showing an example of a water decomposition apparatus using the radioactive catalyst of the present invention. 1 334091 PREFERRED EMBODIMENTS OF THE INVENTION
Fig. 1 is an explanatory view showing the radioactive catalyst and the oxidation-reduction reaction using the catalyst in accordance with the present invention. The respective particles of the radioactive catalyst 10 has a structure wherein a high radioactive platinum group element 14 such as ruthenium-106 is deposited or supported on a fine particle of n-type semiconductor 12 such as titanium oxide.
The platinum group elements recovered from the spent nuclear fuel can be employed as the platinum group element of the radioactive catalyst 10. Besides ruthenium, rhodium or palladium may be used as the platinum group element. From the aspect of high radioactivity, however, preferred is ruthenium-106.
The fluid to be processed is brought into contact with the radioactive catalyst 10. The example of the fluid to be processed is water. If water is used, hydrogen and oxygen can be produced by the oxidation-reduction reaction. In Fig. 1, the lower half represents an energy diagram. When the fine particle of semiconductor 12 is excited by the high radiation energy generated from the radioactive platinum gruop element 14, electrons are produced and gathered at the conduction band (C.B.) while positive holes are produced and gathered at the valence band (~.B.). The radiation energy generated from the high radioactive platinum group element 14 is from about 105 to about 106 eV and is by far greater than the band gap of the fine particle of semiconductor 12 so that a large number of electron-hole pairs can be formed.
The oxidation-reduction reaction such as the decomposition of water can be carried out by utilizing these large number of electron-hole pairs. In other words, hydrogen ions are reduced to hydrogen gas by the electrons in the conduction band while hydroxyl ions are oxidized to produce oxygen gas by the positive holes in the valence band. In the present invention, since the radioactive catalyst itself has the action of the generation source of the reaction energy as well as the action of the catalyst, the oxidation-reduction reaction can always be continued by merely bringing the fluid to be processed into contact with the catalyst.
The result of tentative calculation when hydrogen and oxygen are produced by using the radioactive catalyst of the present invention will be described hereinbelow. It is assumed that ruthenium-106 recovered from the spent nuclear fuel is used as the high radioactive platinum group element.
Radioactivity of ruthenium-106 is 3,300 Ci/g 106Ru. The radiation energy of about 500 keV resulted from l06Rh which is a decay product of 106Ru and in radiation equilibrium with 106Ru, is assumed to be all the energy contributed to the reaction, and the radiation energy resulted from the other ~ rays is neglected. All of this radiation energy are assumed to contribute to the formation of the electron- hole pairs and all of the resulting electron-hole pairs are assumed to contribute to the decomposition of water.
(1) Since the decay constant is 3.7 x 1010, the resulting electron-hole pairs per hour are given as follows:
' 3,300 Ci/g 106Ru x 3.7 x 101 x 5 x 105 eV/3eV x 60 min x 60 sec = 7.33 x 1022 (2) The amount of the produced hydrogen gas per hour is given as follows:
7.33 x 1022/2 x 6.02 x 1023 =6.07 x 10-2 mol H2/hr =1.35 Q H2/hr.
(3) Accordingly, the rcovery amount of Ru required for a pilot plant (lm3 H2/hr) is given as follows:
1,000 R/1.35 ~ ~ 0.74 Kg 106Ru Since 106Ru/Ru = 0.05, 0.74/0.05 = 14.8 Kg Ru (the recovered amount of Ru) This amount of ruthenium corresponds,to the recovery amount from 10 tons of the spent fuel from a light water reactor and is sufficiently practical amount.
Fig. 2 shows an example of a water decomposition apparatus according to the present invention. This represents an example of a single reaction column system. A
plurality of particles of radioactive catalyst 10 are packed into a tubular reaction container or column 20 and water 22 as a fluid to be processed is introduced into the tubular reaction column 20. The particles of the radioactive catalyst is prepared by depositing a high radioactive platinum group element on a fine particle of semiconductor, 1 3340q 1 as described hereinbefore. A valve 24 is disposed at the upper part of the reaction column 20 and is connected to a gathering pipe 28 through a flange 26. A plurality of reaction columns 20 having the radioactive catalyst particles packed therein are juxtaposed with one another.
The gathering pipe 28 is connected to a hydrogen strage tank 30 in which a hydrogen strage alloy is packed. A water supply pipe 32 is connected to each reaction column 20.
Water 22 is decomposed by the radioactive catalyst 10 to thereby produce oxygen and hydrogen. They are introduced through the gathering pipe 28 into the hydrogen strage tank 30 in which only hydrogen is absorbed and oxygen passes as it is. Hydrogen absorbed by the hydrogen strage alloy is desorbed and separated by another cycle and is taken out as a hydrogen gas. A plurality of hydrogen strage tanks 30 may be juxtaposed with one another so that when part of them is operated in the hydrogen absorption cycle, the rest are operated in the hydrogen desorption cycle. In this manner, the continous operation can be carried out.
There is no possibility that the hydrogen gas and oxygen gas thus withdrawn are contaminated by radioactivity.
Therefore, they can be utilized as clean energy. Water consumed due to the decomposition in the column 20 may be suitably supplemented from the water supply pipe 32.
Once the apparatus has been installed, it can be continuously operated night and day for at least about two years by merely supplementing water without necessity of g 1 3340q 1 maintenance and replacement. The half life of ruthenium-106 is 368 days. When it is desired to use it as the catalyst even after the half life, each reaction column 20 may be installed inside a radioactive liquid waste tank (not shown). Namely, by introducing a high radioactive liquid waste tlO5 - 106 Ci/tank) into the tank to utilize the radioactivity thereof, the decomposition of water may successively be carried out in the reaction column installed inside the tank.
As being understood from the foregoing, according to the radioactive catalyst of the present invention wherein the high radioactive platinum gruop element is deposited on the fine particle of semiconductor, the oxidation-reduction reaction can be carried out at a high efficiency, since the catalyst itself has the action of the high energy radiation source as well as the action of the catalyst and since the radiation generated from inside is used as the reaction energy.
Therefore, the catalyst of the present invention is free from the drawbacks of the prior art photocatalyst utilizing the solar rays in that the solar energy is relatively low and depends on the weather and day and night, and the rays of light cannot irradiate all of the photocatalyst particles if the concentration of the photocatalyst particles is high.
Thus, according to the method and apparatus using the radioactive catalyst of the present invention, freedom of design of the apparatus is high, and the apparatus can be l 3~40~ 1 assembled compactly so that the limitations to the installation space thereof are small.
In addition, since the radioactive substances recovered from the spent nuclear fuel such as ruthernium-106 can be utilized, effective utilization of the high radioactive wastes can be made.
Furthermore, since the rays of light are not used, the reaction proceeds inside the sealed container of a metal or the like and the apparatus can be assembled at a low cost.
Once installed, the apparatus does not need maintenance and replacement for a few years so that maintenance becomes easier and the operation cost becomes extremely low.
1,000 R/1.35 ~ ~ 0.74 Kg 106Ru Since 106Ru/Ru = 0.05, 0.74/0.05 = 14.8 Kg Ru (the recovered amount of Ru) This amount of ruthenium corresponds,to the recovery amount from 10 tons of the spent fuel from a light water reactor and is sufficiently practical amount.
Fig. 2 shows an example of a water decomposition apparatus according to the present invention. This represents an example of a single reaction column system. A
plurality of particles of radioactive catalyst 10 are packed into a tubular reaction container or column 20 and water 22 as a fluid to be processed is introduced into the tubular reaction column 20. The particles of the radioactive catalyst is prepared by depositing a high radioactive platinum group element on a fine particle of semiconductor, 1 3340q 1 as described hereinbefore. A valve 24 is disposed at the upper part of the reaction column 20 and is connected to a gathering pipe 28 through a flange 26. A plurality of reaction columns 20 having the radioactive catalyst particles packed therein are juxtaposed with one another.
The gathering pipe 28 is connected to a hydrogen strage tank 30 in which a hydrogen strage alloy is packed. A water supply pipe 32 is connected to each reaction column 20.
Water 22 is decomposed by the radioactive catalyst 10 to thereby produce oxygen and hydrogen. They are introduced through the gathering pipe 28 into the hydrogen strage tank 30 in which only hydrogen is absorbed and oxygen passes as it is. Hydrogen absorbed by the hydrogen strage alloy is desorbed and separated by another cycle and is taken out as a hydrogen gas. A plurality of hydrogen strage tanks 30 may be juxtaposed with one another so that when part of them is operated in the hydrogen absorption cycle, the rest are operated in the hydrogen desorption cycle. In this manner, the continous operation can be carried out.
There is no possibility that the hydrogen gas and oxygen gas thus withdrawn are contaminated by radioactivity.
Therefore, they can be utilized as clean energy. Water consumed due to the decomposition in the column 20 may be suitably supplemented from the water supply pipe 32.
Once the apparatus has been installed, it can be continuously operated night and day for at least about two years by merely supplementing water without necessity of g 1 3340q 1 maintenance and replacement. The half life of ruthenium-106 is 368 days. When it is desired to use it as the catalyst even after the half life, each reaction column 20 may be installed inside a radioactive liquid waste tank (not shown). Namely, by introducing a high radioactive liquid waste tlO5 - 106 Ci/tank) into the tank to utilize the radioactivity thereof, the decomposition of water may successively be carried out in the reaction column installed inside the tank.
As being understood from the foregoing, according to the radioactive catalyst of the present invention wherein the high radioactive platinum gruop element is deposited on the fine particle of semiconductor, the oxidation-reduction reaction can be carried out at a high efficiency, since the catalyst itself has the action of the high energy radiation source as well as the action of the catalyst and since the radiation generated from inside is used as the reaction energy.
Therefore, the catalyst of the present invention is free from the drawbacks of the prior art photocatalyst utilizing the solar rays in that the solar energy is relatively low and depends on the weather and day and night, and the rays of light cannot irradiate all of the photocatalyst particles if the concentration of the photocatalyst particles is high.
Thus, according to the method and apparatus using the radioactive catalyst of the present invention, freedom of design of the apparatus is high, and the apparatus can be l 3~40~ 1 assembled compactly so that the limitations to the installation space thereof are small.
In addition, since the radioactive substances recovered from the spent nuclear fuel such as ruthernium-106 can be utilized, effective utilization of the high radioactive wastes can be made.
Furthermore, since the rays of light are not used, the reaction proceeds inside the sealed container of a metal or the like and the apparatus can be assembled at a low cost.
Once installed, the apparatus does not need maintenance and replacement for a few years so that maintenance becomes easier and the operation cost becomes extremely low.
Claims (7)
1. A radioactive catalyst comprising a fine particle of semiconductor and a high radioactive platinum group element deposited on said particle of semiconductor, whereby said radioactive catalyst serves as a source of radiation and also as a catalyst for oxidation-reduction reaction.
2. The radioactive catalyst according to claim 1, wherein said high radioactive platinum group element comprises ruthenium-106 recoverd from a spent nuclear fuel.
3. An oxidation-reduction method comprising bringing the radioactive catalyst according to claim 1 into contact with a fluid to be processed to produce electron-hole pairs in the semiconductor of said catalyst by the radiation generated from said high radioactive platinum group element deposited on said semiconductor particle, thereby causing the oxidation-reduction reaction.
4. The method according to claim 3, wherein said fluid to be processed is water which is decomposed by the oxidation-reduction reaction to produce hydrogen and oxygen.
5. An oxidation-reduction apparatus comprising a container in which the radioactive catalyst according to claim 1 is packed, means for supplying a fluid to be processed into said container, and means for discharging products of oxidation-reduction reaction from said container.
6. The apparatus according to claim 5, wherein said fluid to be processed is water which is decomposed by the oxidation-reduction reaction to produce hydrogen and oxygen.
7. The apparatus according to claim 6, wherein said means for discharging products from said container is connected to a tank in which a hydrogen strage alloy is packed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63248755A JPH0295440A (en) | 1988-10-01 | 1988-10-01 | Radiation catalyst, oxidation-reduction method and apparatus using same |
| JP63-248755 | 1988-10-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1334091C true CA1334091C (en) | 1995-01-24 |
Family
ID=17182895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000612542A Expired - Fee Related CA1334091C (en) | 1988-10-01 | 1989-09-22 | Radioactive catalyst and oxidation-reduction method and apparatus using same |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5093302A (en) |
| JP (1) | JPH0295440A (en) |
| CA (1) | CA1334091C (en) |
| DE (1) | DE3932670C2 (en) |
| FR (1) | FR2637199B1 (en) |
| GB (1) | GB2223422B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5200254A (en) * | 1992-03-11 | 1993-04-06 | Minnesota Mining And Manufacturing Company | Receptor sheet manifolds for thermal mass transfer imaging |
| WO1993025468A1 (en) * | 1992-06-11 | 1993-12-23 | Pegol Bjhq Company Limited | A method for the production of hydrogen from a water medium |
| US5799257A (en) * | 1992-10-27 | 1998-08-25 | Lockheed Martin Idaho Technologies Company | Process for gamma ray induced degradation of polychlorinated biphenyls |
| JP2531116Y2 (en) * | 1993-11-18 | 1997-04-02 | 興和化成株式会社 | Rail fastening structure for rail widening |
| DE19758512C2 (en) * | 1997-07-18 | 2000-06-29 | Bruker Saxonia Analytik Gmbh | Ion-mobility spectrometer |
| DE102008036368A1 (en) * | 2008-08-05 | 2010-02-11 | Mol Katalysatortechnik Gmbh | Device for generating and storing hydrogen |
| US10882742B2 (en) | 2016-02-02 | 2021-01-05 | Sabic Global Technologies B.V. | Process for separation of hydrogen and oxygen |
| WO2017134535A1 (en) | 2016-02-02 | 2017-08-10 | Sabic Global Technologies B.V. | Process for separation of hydrogen and oxygen |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3287171A (en) * | 1963-01-11 | 1966-11-22 | Exxon Research Engineering Co | Platinum-rhenium anodic oxidation catalyst |
| US4121984A (en) * | 1973-11-09 | 1978-10-24 | Texas Gas Transmission Corporation | Production of hydrogen by radiolysis |
| FR2302274A1 (en) * | 1975-02-28 | 1976-09-24 | Metaux Precieux Cie | Thermal decompsn. of high temp. steam - using palladium as catalyst to mfr. hydrogen for use as a fuel |
| DE2614546A1 (en) * | 1976-04-03 | 1977-10-06 | Gen Electric | PROCESS FOR REDUCING THE CHLORATE CONTENT OF AN AQUATIC, CHLORATE-CONTAINING ALKALIMETAL HYDROXIDE SOLUTION |
| JPS5368718A (en) * | 1976-11-27 | 1978-06-19 | Nippon Kayaku Co Ltd | Simultaneous preparation of methacrylic acid and its ester or acrylicacid and its ester |
| US4205959A (en) * | 1976-12-29 | 1980-06-03 | Michie Ito | Irradiated liquid fuel, method of decrease of proportion in noxious ingredients in exhaust gas and method of reduction of fuel consumption |
| US4264421A (en) * | 1979-05-30 | 1981-04-28 | Board Of Regents, University Of Texas System | Photocatalytic methods for preparing metallized powders |
| GB2058839B (en) * | 1979-09-08 | 1983-02-16 | Engelhard Min & Chem | Photo electrochemical processes |
| EP0043251B1 (en) * | 1980-06-30 | 1984-10-03 | SIBIT S.p.A. | Catalyst for the photodecomposition of water, and a process for the preparation thereof |
| FR2493181A1 (en) * | 1980-11-05 | 1982-05-07 | Centre Nat Rech Scient | Photo:catalysts, esp. for photolysis of water - comprising semiconductor and group VIIa or Gp=VIII metal |
| CH644471A5 (en) * | 1981-02-02 | 1984-07-31 | Michael Graetzel | PRODUCT FOR USE AS A PHOTOCATALYST, PROCESS FOR PREPARING THE SAME AND USE OF THE SAME. |
| DE3261445D1 (en) * | 1981-06-03 | 1985-01-17 | Graetzel Michael | Process for producing hydrogen and elemental sulphur by photochemical redox reaction of hydrogen sulphide and sulphides |
| FR2527098B1 (en) * | 1982-05-24 | 1986-11-14 | Prod Catalyse Ste Fse | NO |
| US4532026A (en) * | 1982-07-06 | 1985-07-30 | Chevron Research Company | Method to improve circulation control in fluidized systems |
| US4598128A (en) * | 1983-03-14 | 1986-07-01 | Phillips Petroleum Company | Polymer composition and preparation method |
| FR2549389A1 (en) * | 1983-07-19 | 1985-01-25 | Centre Nat Rech Scient | HYDROCARBON HYDROTREATMENT CATALYST, PREPARATION AND APPLICATION THEREOF |
| EP0233498B1 (en) * | 1986-01-22 | 1991-08-21 | Hitachi, Ltd. | Process and apparatus of photoelectrocalalytically reducing noble metals in a nitric acid solution |
-
1988
- 1988-10-01 JP JP63248755A patent/JPH0295440A/en active Granted
-
1989
- 1989-09-20 GB GB8921275A patent/GB2223422B/en not_active Expired - Fee Related
- 1989-09-22 CA CA000612542A patent/CA1334091C/en not_active Expired - Fee Related
- 1989-09-22 FR FR898912464A patent/FR2637199B1/en not_active Expired - Fee Related
- 1989-09-29 DE DE3932670A patent/DE3932670C2/en not_active Expired - Fee Related
-
1990
- 1990-12-21 US US07/631,998 patent/US5093302A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0295440A (en) | 1990-04-06 |
| FR2637199A1 (en) | 1990-04-06 |
| US5093302A (en) | 1992-03-03 |
| JPH0553543B2 (en) | 1993-08-10 |
| FR2637199B1 (en) | 1991-02-15 |
| GB2223422B (en) | 1992-02-12 |
| DE3932670C2 (en) | 1998-07-23 |
| DE3932670A1 (en) | 1990-04-05 |
| GB2223422A (en) | 1990-04-11 |
| GB8921275D0 (en) | 1989-11-08 |
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